187 research outputs found
Wavelength transduction from a 3D microwave cavity to telecom using piezoelectric optomechanical crystals
Microwave to optical transduction has received a great deal of interest from
the cavity optomechanics community as a landmark application for
electro-optomechanical systems. In this Letter, we demonstrate a novel
transducer that combines high-frequency mechanical motion and a microwave
cavity for the first time. The system consists of a 3D microwave cavity and a
gallium arsenide optomechanical crystal, which has been placed in the microwave
electric field maximum. This allows the microwave cavity to actuate the
gigahertz-frequency mechanical breathing mode in the optomechanical crystal
through the piezoelectric effect, which is then read out using a telecom
optical mode. The gallium arsenide optomechanical crystal is a good candidate
for low-noise microwave-to-telecom transduction, as it has been previously
cooled to the mechanical ground state in a dilution refrigerator. Moreover, the
3D microwave cavity architecture can naturally be extended to couple to
superconducting qubits and to create hybrid quantum systems
Real estate investment and urban density: Exploring the polycentric urban region using a topological lens
Focusing on commercial office real estate as both a manifestation of and a conduit of cross-border capital ïŹows, this paper refers to the concepts of topology and topography in a theoretical and empirical exploration of contemporary ânetwork economyâ spatial implications for the âpolycentric urban regionâ (PUR). A body of research has cast doubt on the normative European representation of the multi-centre PUR as a balanced, sustainable spatial development model. Yet, the model has continued to be propagated in European territorial strategy and has been influential internationally. Academic perspectives and qualitative evidence reviewed in the paper shed a light on mutual dependencies and recursive relations between network economy global structural processes, international office real estate investment practices mediated by city governments, and the spatial configuration of density. Commercial investment and city planning actor practices chime with urban agglomeration, spatial concentration and density. Quantitative evidence of associations between urban density and office real estate investment returns and capital flows is found. It is concluded that network economy topology, politics and the city are in a dialectical relationship with the PUR territorial governance agenda for spatially balanced regional development
Cellular adaptations to hypoxia and acidosis during somatic evolution of breast cancer
Conceptual models of carcinogenesis typically consist of an evolutionary sequence of heritable changes in genes controlling proliferation, apoptosis, and senescence. We propose that these steps are necessary but not sufficient to produce invasive breast cancer because intraductal tumour growth is also constrained by hypoxia and acidosis that develop as cells proliferate into the lumen and away from the underlying vessels. This requires evolution of glycolytic and acid-resistant phenotypes that, we hypothesise, is critical for emergence of invasive cancer. Mathematical models demonstrate severe hypoxia and acidosis in regions of intraductal tumours more than 100 m from the basement membrane. Subsequent evolution of glycolytic and acid-resistant phenotypes leads to invasive proliferation. Multicellular spheroids recapitulating ductal carcinoma in situ (DCIS) microenvironmental conditions demonstrate upregulated glucose transporter 1 (GLUT1) as adaptation to hypoxia followed by growth into normoxic regions in qualitative agreement with model predictions. Clinical specimens of DCIS exhibit periluminal distribution of GLUT-1 and Na+/H+ exchanger (NHE) indicating transcriptional activation by hypoxia and clusters of the same phenotype in the peripheral, presumably normoxic regions similar to the pattern predicted by the models and observed in spheroids. Upregulated GLUT-1 and NHE-1 were observed in microinvasive foci and adjacent intraductal cells. Adaptation to hypoxia and acidosis may represent key events in transition from in situ to invasive cancer
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Supporting smart urban growth: successful investing in density
This report analyses the characteristics of âgood densityâ and begins to quantify the relation-ship between these characteristics, investor returns, and carbon emissions. We found that cities with good density â that is, dense development thoughtfully designed to promote a high quality of life â are likely to be more resilient and prosperous in the long term, and there-fore more likely to provide sustainable returns for investors, than cities without good density. Based on a quantitative analysis of 63 global cities, the report finds that cities with good density are associated with higher returns, capital values, and levels of investment flows for commercial real estate. The research provides evidence of important issues for the long-term resilience of cities both in the OECD and in fast-growing developing regions
Why is it difficult to implement e-health initiatives? A qualitative study
<b>Background</b> The use of information and communication technologies in healthcare is seen as essential for high quality and cost-effective healthcare. However, implementation of e-health initiatives has often been problematic, with many failing to demonstrate predicted benefits. This study aimed to explore and understand the experiences of implementers - the senior managers and other staff charged with implementing e-health initiatives and their assessment of factors which promote or inhibit the successful implementation, embedding, and integration of e-health initiatives.<p></p>
<b>Methods</b> We used a case study methodology, using semi-structured interviews with implementers for data collection. Case studies were selected to provide a range of healthcare contexts (primary, secondary, community care), e-health initiatives, and degrees of normalization. The initiatives studied were Picture Archiving and Communication System (PACS) in secondary care, a Community Nurse Information System (CNIS) in community care, and Choose and Book (C&B) across the primary-secondary care interface. Implementers were selected to provide a range of seniority, including chief executive officers, middle managers, and staff with 'on the ground' experience. Interview data were analyzed using a framework derived from Normalization Process Theory (NPT).<p></p>
<b>Results</b> Twenty-three interviews were completed across the three case studies. There were wide differences in experiences of implementation and embedding across these case studies; these differences were well explained by collective action components of NPT. New technology was most likely to 'normalize' where implementers perceived that it had a positive impact on interactions between professionals and patients and between different professional groups, and fit well with the organisational goals and skill sets of existing staff. However, where implementers perceived problems in one or more of these areas, they also perceived a lower level of normalization.<p></p>
<b>Conclusions</b> Implementers had rich understandings of barriers and facilitators to successful implementation of e-health initiatives, and their views should continue to be sought in future research. NPT can be used to explain observed variations in implementation processes, and may be useful in drawing planners' attention to potential problems with a view to addressing them during implementation planning
Information flows at inter-team boundaries in agile information systems development
Agile software development methods are being used on larger projects thus the study of inter-team communication are becoming an important topic of interest for researchers. This research addresses inter-team communication by exploring the tools and three different boundaries, inter-team, team and customers, and geographically separated teams. In this research, we gathered data from semi-structured face-to-face interviews which were analyzed following the grounded theory approach. Our study reveals consensus from different teams on the importance of virtual Kanban boards. Also, some teams members tend to adapt to other teamsâ preferred communication tool. We observed challenges around interdependent user stories among the different teams and highlighted the problems that rise at the different boundaries.
Keywords: agile information system development âą inter-team communication âą agile team boundary âą communication âą agile methods âą cooperating agile team
The next detectors for gravitational wave astronomy
This paper focuses on the next detectors for gravitational wave astronomy
which will be required after the current ground based detectors have completed
their initial observations, and probably achieved the first direct detection of
gravitational waves. The next detectors will need to have greater sensitivity,
while also enabling the world array of detectors to have improved angular
resolution to allow localisation of signal sources. Sect. 1 of this paper
begins by reviewing proposals for the next ground based detectors, and presents
an analysis of the sensitivity of an 8 km armlength detector, which is proposed
as a safe and cost-effective means to attain a 4-fold improvement in
sensitivity. The scientific benefits of creating a pair of such detectors in
China and Australia is emphasised. Sect. 2 of this paper discusses the high
performance suspension systems for test masses that will be an essential
component for future detectors, while sect. 3 discusses solutions to the
problem of Newtonian noise which arise from fluctuations in gravity gradient
forces acting on test masses. Such gravitational perturbations cannot be
shielded, and set limits to low frequency sensitivity unless measured and
suppressed. Sects. 4 and 5 address critical operational technologies that will
be ongoing issues in future detectors. Sect. 4 addresses the design of thermal
compensation systems needed in all high optical power interferometers operating
at room temperature. Parametric instability control is addressed in sect. 5.
Only recently proven to occur in Advanced LIGO, parametric instability
phenomenon brings both risks and opportunities for future detectors. The path
to future enhancements of detectors will come from quantum measurement
technologies. Sect. 6 focuses on the use of optomechanical devices for
obtaining enhanced sensitivity, while sect. 7 reviews a range of quantum
measurement options
Beyond adoption: A new framework for theorising and evaluating Non-adoption, Abandonment and challenges to Scale-up, Spread and Sustainability (NASSS) of health and care technologies
© 2017 The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in the Journal of Medical Internet Research, is properly cited. The complete bibliographic information, a link to the original publication on http://www.jmir.org/, as well as this copyright and license information must be included.Background: Many promising technological innovations in health and social care are characterized by nonadoption or abandonment by individuals or by failed attempts to scale up locally, spread distantly, or sustain the innovation long term at the organization or system level. Objective: Our objective was to produce an evidence-based, theory-informed, and pragmatic framework to help predict and evaluate the success of a technology-supported health or social care program. Methods: The study had 2 parallel components: (1) secondary research (hermeneutic systematic review) to identify key domains, and (2) empirical case studies of technology implementation to explore, test, and refine these domains. We studied 6 technology-supported programsâvideo outpatient consultations, global positioning system tracking for cognitive impairment, pendant alarm services, remote biomarker monitoring for heart failure, care organizing software, and integrated case management via data sharingâusing longitudinal ethnography and action research for up to 3 years across more than 20 organizations. Data were collected at micro level (individual technology users), meso level (organizational processes and systems), and macro level (national policy and wider context). Analysis and synthesis was aided by sociotechnically informed theories of individual, organizational, and system change. The draft framework was shared with colleagues who were introducing or evaluating other technology-supported health or care programs and refined in response to feedback. Results: The literature review identified 28 previous technology implementation frameworks, of which 14 had taken a dynamic systems approach (including 2 integrative reviews of previous work). Our empirical dataset consisted of over 400 hours of ethnographic observation, 165 semistructured interviews, and 200 documents. The final nonadoption, abandonment, scale-up, spread, and sustainability (NASSS) framework included questions in 7 domains: the condition or illness, the technology, the value proposition, the adopter system (comprising professional staff, patient, and lay caregivers), the organization(s), the wider (institutional and societal) context, and the interaction and mutual adaptation between all these domains over time. Our empirical case studies raised a variety of challenges across all 7 domains, each classified as simple (straightforward, predictable, few components), complicated (multiple interacting components or issues), or complex (dynamic, unpredictable, not easily disaggregated into constituent components). Programs characterized by complicatedness proved difficult but not impossible to implement. Those characterized by complexity in multiple NASSS domains rarely, if ever, became mainstreamed. The framework showed promise when applied (both prospectively and retrospectively) to other programs.Peer reviewe
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